The application generally relates to the control and operation of a chain drive. The application relates more specifically to a control system to control the operation of one or more chain drives in which the control instructions for the chain drive are generated from the execution of a control algorithm by a microprocessor incorporated in the chain drive.
Chain drives or chain hoists can be used in a variety of different environments, such as a manufacturing plant, a warehouse, or in the entertainment industry. When used in the entertainment industry, chain drives can be used in the assembly and disassembly of stage components and to move objects such as scenery and/or curtains during a performance.
A chain drive or chain hoist can be attached to an overhead beam or other support structure and can be used to raise or lower an object(s) connected to the chain drive. One way to control the operation of the chain drive is by the manual operation of corresponding command buttons on a control device associated with the chain drive. For example, an operator can press an “up” button on the control device to operate the chain drive to raise the object and can press a “down” button on the control device to operate the chain drive to lower the object. However, the control of the chain drive using the control device can be imprecise due to the operator input requirement. For example, the operator may not be able to obtain a desired position for the chain drive because the operator is unable to stop the chain drive at the desired position due to an inability to press a command button at the appropriate time.
Another way to control the operation of a chain drive is to provide control instructions to the chain drive from a remotely located controller. The remotely located controller can be incorporated with a user interface for the system or can be an intermediate controller, sometimes referred to as a stack, located between the user interface and the chain drive. The controller generates and provides the individual instructions to the chain drive, e.g., raise or lower commands, similar to the instructions provided to the chain drive by the control device. In addition, the controller can receive feedback information from the chain drive relating to the operational status of the chain drive. The controller can provide control instructions to multiple chain drives in order to sequence or coordinate the operation of the chain drives. For example, a controller can be used to coordinate the operation of several chain drives to raise or lower a curtain at the same time and speed. One drawback to the centralized control of multiple chain drives with the controller is that as the number of chain drives in a particular system increases, the processing power or capability of the controller and the controller's corresponding communication bandwidth has to likewise increase in order to be able to provide the appropriate control instructions to the chain drives and receive the corresponding feedback from the chain drives. If the controller cannot process the information and instructions fast enough, the chain drive system may not perform as expected and/or safety risks could be introduced that could cause damage or injury to both people and property. In addition, the use of a controller with an individual chain drive for the assembly and disassembly process would be inefficient and expensive.
Therefore, what is needed is a control system for one or more chain drives that enables the control instructions for the chain drive to be generated using a controller incorporated into the chain drive.